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Old January 23rd, 2014, 05:36 PM
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Default Re: HAL Placement-Paper

Hindustan Aeronautics Limited is a public sector company under the Ministry of Defense. The company is mainly engaged in aerospace industry and manufactures and assembles aircraft.

The company is also involved in operating airports and manufactures navigation equipments. HAL is one of the biggest aerospace companies in Asia and is based in Bangalore.

HAL Placement-Paper:

1. When length of a wire increases its resistance
a. doubles
b. half
c. remains same
Ans: ( a )

2. When a 50 Hz ,6-pole Induction Motor runs at 975rpm,the rotor emf frequency is
a. 12.5Hz
b. 1.25Hz
c. 4Hz
Ans: ( b )

3. When a 6 pole 50Hz Induction Motor runs at 1450 rpm , it’s working mode is
a. motoring
b. braking
c. generating

Ans: ( a )

4. Slips for Different modes of operation of Induction Motor are
answer: motoring -01

5. Damping ratio ( ? ) is 0.75, natural frequency is 12 rad/s are given & asked to find peak time

6. In electrodynamo-meter type wattmeter
a. pressure coil is made fixed
b. current coil is made fixed
c. both the coils are made fixed
Ans: ( a )

7. In flux meter control torque is produced by
a. weights attached to it.
b. Springs
c. No control torque is there
Ans: ( c )

8. One question regarding hot wire instrument

9. In MI meters deflecting torque is proportional to
a. square of the current
b. square of the voltage
Ans: ( a )

10.In 3-F system total power is given by
a. v3VLILcos F
b. 3VLILcos F
c. VLILcos F
Ans: ( a )

11.From supply one 3-F step-down transformer is drawing 10 A, the secondary current will be minimum when the transformer is
a. star-delta
b. delta-star
c. delta-delta
d. star-star
Ans: ( b )

12.Transformer rating is expressed in
a. KVA
c. KW
Ans: ( a )

13.Manganin is a
a. Insulator
b. Semi-conductor
c. Alloy

14.Dual scope oscilloscope has
a. two separate horizontal and two separate vertical plates
b. one horizontal and two separate vertical plates
c. two separate horizontal and one vertical plates
d. one horizontal and one vertical plates

15.Standard Cell voltage is measured by
a. MI meter
b. MC meter
c. Potentiometer

16.The input resistance of the CRO is of the order of
a. tens of ohm
b. mega ohm
c. kilo ohm
d. fraction of an ohm
Ans: ( b )

17.Errors are introduced in Wheatstone bridge due to
a. lead resistance
b. contact resistance
c. some thing is given
d. all of the above

18.HRC fuse and circuit-breaker combination is used CB operates for
a. low over-load currents
b. high over-load currents
c. combination is never used

19.G(s) = K / s(s+5)(s+1) is given to find the value of K for stable operation

20.By increasing gain of the system root locus will
a. moves away from poles
b. moves away from zeros
c. crosses imaginary axis
Ans: ( a )

21.When the load current is high while measuring power using wattmeter
a. current coil is connected near load
b. pressure coil is connected near load

22.C = 0.01µF and L = 1 mH and current is 10 A and asked to find the voltage drop

23.Transmission line is terminated by R and no reflection is there , then the value of R is
Ans: 400 ohm

24.One question regarding shunt ohm-meter and seriea ohm-meter

25.Inverted V curves are drawn between ________

Ans: field current Vs power factor
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Old February 25th, 2015, 12:35 PM
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Join Date: Nov 2011
Default Re: HAL Placement-Paper

Ok, as you want the placement paper of HAL so here I am providing you.

HAL Placement Paper

1) Finding the power angel in power system

2) The motor used in fruit juicer

3) LVDT is used in finding th displacement

4) Cross magnetization will come with wat pf

5) The type of converter used in HVDC

6) The relationship b/w the airgap and current in light

7) Corrona loss is less in which type of shaped conductor? (the question is asked 2 times)
Ans: circular

8) The motor used in low speed applications?

9) If the accuracy of an instrument is 5% for 100A current, accuracy for 50A current?

10) A question on time constant of a coil(R-L) circuit!

11) Effect of line commutated inductance in inverter
a) increase current ripple
b) reduces current ripple
c) increases output voltage
d) reduces output voltage

12) The type of bridge is used for Low Q applications
ans: maxwells bridge

13) A question on PSM and TSM in power system

14) The advantage of PI controller over P controller

15) The power gain is highest in wat amplifier
Ans : common emitter

16) Power of a converter with ac input supply and dc output current
a)1 b)0.98 c)0.95 d)0.92

17) The element which has unchanged properties when current direction is reversed
a)linear b)bilateral
Ans: b

18) The output voltage is high in wat rectifier
a) HWR b) FWR

19) Problem on power factor..a load is given and synch motor is given..sych motor is taking 10kw input, load is 00MVA and 0.8lag,synch motor is running on no load..to bring power factor to '1' the synch motor should supply how much eactive VAR?

20) A question on current source and voltage source inverter power transformer is earthed becoz..
a) to reduce neutral current
b) to avoid harmonics

21) Why generator neutral is earthed with transformer neutral?
Ans: generator stator winding protection

22) Positive sequence terminal voltage is zero in
Ans: d

23) A bit on finding the voltage drop in the line when the supply voltage and line reactance and VARs supplied to the
load in p.u.

24) Pulse transformer is used in thyristor because?

25) The advantage of linear power supply over switched mode power supply?
a)low cost
b)low noise
c)low weight

26) The stability when there are slow changes in load
Ans: steady state stability

27) A question on finding the step angle of a stepper motor

28) A question on construction of hybrid motor

29) Which answer is not true in case of squirrel cage IM
a)resistance is low
b)the cross section of copper conductors is low
d)none of the above
Ans: a

30) To increase starting torque of SRIM
Ans: add resistance

31) Which torque is maximum in stepper motor
a) starting torque
b) pullout torque
c) hybrid torque

32) The similarity b/w in 8086 and 8088
Ans: data bus(16bit)

33) The location transferred by the processor when INTR is enabled
Ans: it wont go to any location since it is non vectored inturrept

34) The starting torque relation b/w DOL starting and star-delta starting
Ans: star delta starting torque is 1/3 times lower

35) THD in full wave rectifier?

36) A question on third harmonic power in full wave converter

37) Element of high negative temp coeff

38) In parallel with each of the main breaks is a low ohmic resistor which is used for
Ans: reducing the rate of rise of the recovery voltage during an interrupting operation

39) Recovery voltage of a circuit breaker is defined as
Ans: instantaneous value of the supply voltage when the current is interrupted

40) A question on different types of FACTS

41) Kelvin double bridge is used for measurement of?
ans: low resistance

42) Speed control of IM using slip change method
a) using freq
b) using changing the no. of poles
c) cascade control

43) Two cycles are there in in oscilloscope..then the freq ration x and y axix( lissajous figure )

44) What is the universal gate
a) and b) not c) Exor d) nor
Ans: d

45) Fleming's left hand rule is used for?
Ans : dc motor

46) A question on circuit breaker operating time( time between relay command and opening of the contacts of CB)

47) Given reactance of a line 4%, asked the short circuit capacity
Ans: 25 times rated current

48) By keeping applied voltage constant if freq is decreased
Ans: iron losses increases

49) When 3 phase induction generator is stable
a) rotor rotating at less than synch speed
b) rotor rotating at higher than sych speed

50) Why rotor bars are skewed in IM
Ans: to reduce locking tendency

51) Large size alternators are excited with?

52) The time taken by the gas turbine to come into normal speed after it is stopped
a)1hr b)30min

53) Most economical load in underground cable
a) less than surge impedance
b) equal to surge impdance
c) more than surge impedence

54) Given load factor and plant factor and given maximum demand, they have asked to find out the reserve capacity

55) A question on power measurement when the current coil and voltage coil are connected in weird manner

56) The SI unit of power

57) Conductor size is based on ?
a) depeding upon the transmission line distance
Ans: might be 'a'

58) Which of the following transformers can be connecte in parallel
a) delta-delta, delta-star
b) delta-star, star-star
c) delta-delta, star-star
d) delta-star, star-delta

59) Compensating coil is connected in wat way in lpf wattmeter
Ans: around CC and in series with the PC

60) The input impedance is in the range of ____ in Digital Volt Meter
Ans: in Mega Ohm

61) The input and output impedance of an ideal opamp

62) Two resistances are connected in series and parallel manner..and the values of overall series and parallel connections is given and then asked to find out the two resistances.

63) Question on finding the power angle when the input to the generator is increased

64) Ferranti effect is obtained when?
Ans: when the sending voltage is less than receiving voltage

65) Which type of logic family used in
Ans: Emitter coupled Logic
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